The secretary of state and secretary of defense are set to appear Tuesday before the Senate Foreign Relations Committee, where they’ll be subjected to the first detailed public questioning of the Obama administration since the president called on Congress to authorize an attack on Syria.

President Barack Obama’s national security team has been briefing members of Congress in secret sessions, and its “senior administration officials” have been working the press, but Tuesday’s session will put everyone in the open and on the record.

“The American people deserve to hear more from the administration about why military action in Syria is necessary, what it will achieve and how it will be sufficiently limited to keep the U.S. from being drawn further into the Syrian conflict,” said Tennessee Sen. Bob Corker, the committee’s ranking member. “Now that the president has decided to use force and seek authorization, he must immediately use every resource appropriate in making his case to the public before this potentially defining vote in Congress.”

Here are POLITICO’s top five questions for Vietnam vets and longtime friends Kerry and Hagel, confronting their first major international crisis since entering the executive branch earlier this year.

1. What will Obama do if Congress says no?

“The president has the authority to act, but the Congress is going to do what’s right here” Kerry said as he blanketed all five of Washington’s Sunday morning shows — but few on Capitol Hill seemed to think it was a sure thing as members absorbed Obama’s announcement.

So if the White House doesn’t think it needs Congress, but Obama just wanted to be a nice guy, will it launch a Syria intervention even if lawmakers turn one down? Or what if the Hill authorizes something less than what Obama wants?

Sen. Patrick Leahy (D-Vt.) already has made clear he thinks the draft resolution the White House sent to Congress is too broad and wants his colleagues to consider an even narrower one to limit a potential U.S. intervention.

If Congress prescribes a very limited attack, will the president ignore the Hill’s limitations and act as he sees fit given his power as commander in chief?

2. What is the White House’s endgame after bombing?

Obama, Kerry and other top officials have spent much of their energy so far playing what they feel is the strongest card in their hand: the U.S. intelligence case that Syrian President Bashar Assad ordered a chemical weapons attack Aug. 21 that killed more than 1,400 people.

Few in Washington have wanted to talk about the larger context, however. Suppose the U.S. “punishes” Assad for his chemical attack with “tailored” strikes — and the deadly civil war continues. What then? Both Kerry and the White House have stressed that the goal of an intervention wouldn’t be to depose Assad — the West wants to see him leave power in an orderly, negotiated transition. If an attack won’t help on that score, how should Washington bring that about?

“We will even, I think, sharpen the focus of our efforts to support the opposition, to work with allies and friends in the region, all of whom understand that Assad has lost any legitimacy as the leader of Syria, and to try to hold Syria together with a political solution that can be achieved through the Geneva process,” Kerry said on NBC's “Meet the Press.”

Are these the same “allies and friends” who have so far refused to go along with a U.S. intervention? What effect, senators might ask, would American strikes have on this potential coalition? And given how little the international community has achieved so far in pressuring Assad, would limited military action help — or make any difference at all?

Experts and skeptics worry that one or two days’ worth of cruise missiles might not have any major effect on Assad, although Kerry said Sunday that even a limited attack could still pack a punch.

“Whatever the president ultimately decides to do in that context, I assure you Assad will feel its impact, and they will know that something has happened,” he said.

3. Is the Pentagon still skeptical about intervention?

Hagel and the military’s top uniformed leader, Joint Chiefs Chairman Gen. Martin Dempsey, have spent months cautioning about a potential intervention in Syria. The rebels there are loaded with Al Qaeda fighters, they’ve warned. The complexity of the conflict means Washington may not be able to fully understand or control it. And once the U.S. gets involved, no one may remember the initial intent was for “tailored, limited” strikes.

“You better be damn sure, as sure as you can be, before you get into something, because once you’re into it, there isn’t any backing out, whether it’s a no-fly zone, safe zone, protect these — whatever it is,” Hagel warned a Senate panel in the spring. “Once you’re in, you can’t unwind it. You can’t just say, ‘Well, it’s not going as well as I thought it would go, so we’re going to get out.’”

Hagel and Dempsey have always made clear that they’ll give Obama “military options” and stand ready to execute orders if and when they arrive. But senators skeptical about a Syria intervention may arrive Tuesday armed with a long list of Hagel and Dempsey quotes and ask how the president can back a bombing over the warnings of his top military chiefs.

4. What are the risks of delay?

Obama said that Dempsey has assured him a U.S. strike will be just as effective against Syria “tomorrow or next week or one month from now” as it would have when the White House first began signaling its desire for an attack late Aug. 23.

Senators may very well ask Kerry and Hagel how effective a strike would be if it has been so well telegraphed to the world.

The House isn’t scheduled to reconvene until Sept. 9, and the Senate’s deliberations are legendary. So if Congress does authorize a Syria strike, it might not happen until the middle of the month, by which time Assad will have had ample warning to prepare his military units.

The Tomahawk cruise missiles Obama is said to favor for his “limited” strike can hit targets with GPS precision at long ranges, but they do not pack much of a wallop. So can a “limited, tailored” strike on a dictator who’s had nearly a month to prepare actually have much of an effect?

5. What does success look like?

Before Obama’s decision to go to Congress, the White House aggressively managed expectations for a potential Syria strike. The “limited” goal, it said, was to “punish” Assad for using chemical weapons. Who will assess the success of “punishment,” senators might ask — and might it require multiple attacks instead of just one?

Kerry seemed to leave the door open for that possibility on Sunday’s “Meet the Press,” when host David Gregory asked him whether Americans can be confident a first strike on Syria might be the last.

“That will depend on whether Assad decides to use chemical weapons or not,” Kerry said. “The president of the United States does not intend to and does not want to see the United States assume responsibility for Syria’s civil war. That is not what he is setting out to do. What he is setting out to do is enforce the norm with respect to the international convention on chemical weapons, and it is targeted to do that. It will clearly have an impact on Assad’s military capacity.”

Having an “impact” on Assad’s “capability” can mean a lot of different things. How, when the goal is “punishment,” will the U.S. know when the job is done?